The present invention relates to a multilingual display device and a method thereof and, in particular, to a multilingual display device and a method thereof in which characters are displayed using an on-screen display function in a particular language of an area corresponding to the broadcasting system and the sound multiplex mode after identifying the broadcasting system and the sound multiplex mode of a current received broadcast signal.
Recently, along with the development of electronic technology, the number of functions provided to a television has increased. For example, there are an on-screen display (to be called `OSD` hereinafter) function and a sound multiplex function.
An OSD function is one which displays particular graphic symbols together with character signals on a screen so that a user is easily aware of information such as a control state and a reservation of a television.
A sound multiplex function is one which outputs a plurality of languages through speakers in a single television. The specific modes of the multiplex function include a `main+main,` a `main+sub,` and a `sub+sub` mode. `Main` indicates the main language of a corresponding country, and `sub` indicates a particular language other than the main language of the country.
Accordingly, in the `main+main` mode, a main language is output from the left and right speakers of a television. In the `main+sub` mode, a main language and a secondary language are output separately from the left and right speakers of a television at the same time. In a `sub+sub` mode, a secondary language is output from the left and the right speakers of a television.
FIG. 1 is a block diagram showing a conventional video apparatus which provides the sound multiplex function and the OSD function described above.
In FIG. 1 broadcast signals received through an antenna 2 are input to a tuner 4. Tuner 4 converts an input signal into an intermediate frequency (to be called IF, hereinafter) signal and applies the IF signal to an IF signal processor 6. IF signal processor 6 amplifies and processes the IF signal according to a control signal C2 provided from a microcomputer 8, and outputs the processed IF signal to a sound multiplex processor 10 and a video signal processor 12.
Video signal processor 12 detects a video signal from the processed IF signal, separates color difference signals from the detected video signal, and displays the color difference signals on an image receiving tube 14 as a composite video signal. That is, if the OSD signals (character type/color/size) generated from microcomputer 8 by user operation are input to video signal processor 12, video signal processor 12 mixes the OSD signals with the separated color difference signals and displays the mixed signal on image receiving tube 14 as a composite video signal.
Sound multiplex processor 10 outputs an audio signal in one of the `main+main,` `main+sub,` and `sub+sub` modes according to a control signal C1 provided from microcomputer 8.
There are different modes for processing the sound multiplex signal. For example, a Zenith mode is employed in the U.S.A., a two carrier mode having two carrier signals during a transmission is adopted in Korea, and an FM--FM mode having one carrier signal which is frequency-modulated is adopted in Japan. Sound multiplex processor 10 is made to perform only one of these sound multiplex processing modes.
In the Zenith mode of the U.S.A., an amplitude-modulated pilot signal of 1 f.sub.H (f.sub.H is a horizontal sync frequency having a frequency of 15.734 KHz) is loaded on a sound carrier frequency of 4.5 MHz as an identifying signal for identifying a stereo broadcast mode or bilingual broadcast mode. In the two carrier mode of Korea, an amplitude-modulated pilot signal of 3.5 f.sub.H (55.07 MHz) is loaded on a sound carrier frequency of 4.72 MHz of the second sound channel (L-R). In the FM--FM mode of Japan, a pilot signal frequency-modulated from 3.5 f.sub.H (55.07 KHz) to 922.5 Hz (multiplex broadcast) or 982.5 Hz (stereo broadcast) is loaded on a sound carrier frequency of 4.5 MHz.
The sound multiplex processor of the U.S.A. is disclosed in U.S. Pat. No. 4,953,021 and the sound multiplex processor of Japan is disclosed in U.S. Pat. No. 4,703,501.
The above-described conventional video apparatus shown in FIG. 1 can perform only a particular broadcasting system and the sound multiplex mode of a particular country. Therefore, it cannot receive all the broadcast signals corresponding to broadcasting systems and sound multiplex modes, and can display only the characters of a particular country using an OSD function, thereby lowering interchangeability.